Patent GB-191512561-A (GB)
Title: Improvements in or relating to Telegraph Systems.
IPC: H04L25/42
Filed: 1915-09-01
Abstract: 12,561. British Insulated & Helsby Cables, Ltd., and Harrison, H. H. Sept. 1. Type-printing telegraphs; automatic telegraphs; strip-perforating receivers.-In a system of the kind in which permutations of positive and negative impulses are used to select the desired letter by means of. intermittently-driven distributors, the' distributors are driven or controlled by impulses which are independent of the signalling-impulses, there being no appreciable intervals of zero current between successive signalling-impulses. Keyboard and automatic transmitting systems and two distributor arrangements are described. One distributor is rotated intermittently one step for each impulse in the group of impulses representing a letter, and the other is rotated continuously during the period of a complete letter, being started and stopped at the beginning and end of each letter. First arrangement, Fig. 1, with keyboard transmitter. The keyboard comprises five keys 11, each key being adapted to connect the corresponding segment of the distributors D, E to the negative or positive pole of the batteries B', B<2>. The distributors D, E are mounted on the shaft of an escapement 1, 5, which is controlled by the magnet 2 in such a way that the brush 8 rotates half a segment when the magnet 2 is energized and a further half-segment when it is de-energized. The magnet 2 is controlled by a relay 49, which is itself controlled by the distributor E, which has conducting-segments 46, 57, &c. equal in numbsr to, but half the length of, the segments 36, 55 of the distributor D. The line L is normally connected over the starting-contact 36 of the distributor and armature 32 of the relay 29 to the negative pole of the battery B<1>; but when any key is depressed, the contact 27, 28 closes a circuit through the lower winding of the relay 29 and a condenser 30 shunted by a resistance 31. The charging-impulse of the condenser 30 momentarily energizes the relay 29, but the resistance 31 is too high for the armature 32 to be retained attracted by the lower winding of the relay. The energized relay 29 disconnects the line L from the negative battery B<1> and connects it through its upper winding to the positive battery B<2>, and at the same time closes at contact 44 a circuit through the starting- contact 46 of the distributor E for the relay 49, which energizes the escapement magnet 2, thus allowing the distributors to rotate one step, the brush of distributor E then resting on an insulating-segment. The circuits of the relay 49 and magnet 2 are thus broken, so that the distributors move a further step, the circuit of the relay 49 being then closed over a contact 57 and the first key 11. The distributors are rotated step by step through the number of steps corresponding to the impulses representing a letter, and are then arrested. During this further movement, the brush 8 successively connects the line to the batteries B', B<2>, according to the setting of the keys 11. At the receiving-station, the negative current normally on the line energizes the polarized relay 38 and relay 41 without effect; but when the line current is reversed by the depression of any key, the relay 61 is energized and closes a starting-circuit for the escapement magnet 67 over contacts 66, 62. The magnet 67 is then intermittently energized over the segments of the distributor J when line impulses of either polarity are received. The positive signalling-impulses are repeated over contact 62 to energize certain of the type-selecting magnets 22 .. 26, negative impulses being without effect. Second arrangement with keyboard transmitter. In this arrangement, the distributor is driven continuously during the period of a letter by a friction drive, a catch being removed from an arm on the distributor shaft by a magnet controlled by a contact that is closed when any key is depressed. Third arrangement, Fig. 3, with automatic transmission and strip-perforating receiver. The arrangement of the distributors is the same as that shown in Fig. 1, but at each revolution of the distributor R, its brush 115 energizes a relay 116, which completes the circuit of magnets 105, 113 and the lower winding of relay 89. The magnet 113 withdraws the pins 110 from the tape 100, which is fed one step by the magnet 105. Five pins 110 are carried by five levers 108 and control the connexion of the distributor segments over springs 111 to positive and negative poles of the batteries. This arrangement may be used for multiple-channel working. At the receiver, the segments of the distributer are connected to the paper-feed magnet and the strip-perforating magnets.